The present invention relates to a device for performing turning of objects, in particular elongate objects which are round in cross-section, such as tree trunks, comprising a rigid lever with a handle part at a rear end and, at a front end, a part supporting a circumferential surface, and a hook member which is pivotally connected to the lever in an area between the part supporting a circumferential surface and the handle part in such a manner that the device, when the lever is oriented with its front end in the intended turning direction and at the same time the hook member is directed towards the turning direction, is abuttable, by means of the lever part supporting a circumferential surface, against the object and engageable, by means of the hook member, with the object, thus allowing turning/rotating of the object by a user grasping the handle part and applying a force in the turning direction.
In manual forest work, different types of aids are normally used to facilitate turning of logs so as to reach the logs for limbing or move the logs by rolling. Examples of such aids are ordinary lifting hooks or tongues but also what is referred to as cant hooks of the type described by way of introduction can be used, which have an extended lever in order to increase, by means of leverage, the turning moment on the logs and thus facilitate turning. Such cant hooks are frequently provided with a plate element at their front ends, thereby also allowing use as a felling lever for felling of trees.
A problem when turning not quite symmetrical, heavy objects, such as logs, on an uneven base, is that the logs often tend to roll back to the starting position if the log has not been turned so far that a new position of equilibrium is reached. This causes a great risk of injuries, for instance, if the log rolls back onto the user or if, while trying to make the log reach a new position of equilibrium, he turns the log so far that his body takes an unsuitable working posture, which in unfavorable cases may cause strain injuries.
The invention aims at eliminating the drawbacks in existing turning devices of the type mentioned by way of introduction and providing a turning device which significantly facilitates turning and moving of heavy objects and eliminates or at least reduces the risk of injuries. At least these objects are achieved by means of a turning device according to claim 1.
Thus the invention is based on the knowledge that these objects may be achieved by a turning device which comprises two levers, which each have a hook member and are interconnected via a hinge which allows displacement of the levers in the longitudinal direction relative to each other and turning relative to each other in the plane of the levers. Such a device makes it possible to turn also heavy objects on an uneven base by alternately letting the hook member of one lever being in the engaging position while the other lever is disengaged and moved towards the turning direction so as to take a new engaging position. In this way it is possible to turn the object more quickly, with less effort and without the risk of the object rolling back to its starting position. By making small and short turning movements for each engaging position of the lever, the user can all the time take an ergonomically correct working posture where the major part of the lifting operation can be carried out using his legs.
In a preferred embodiment the hinge is formed as a pivot pin which extends through an elongate slot in each lever. However, the hinge could also be formed in many other ways, for instance by a pivot pin running in a slot in one lever only while the pivot pin is fixedly connected to the other lever, or by a sleeve-shaped part which surrounds the levers from the outside but allows displacement and turning of the levers relative to each other. Many other solutions would also be conceivable within the scope of the claims.
In a preferred embodiment, the hook member is preloaded by means of a spring which strives to pivot the hook member forwards towards the front end of the lever, i.e. towards the object when the lever abuts against the object with its part supporting the circumferential surface. This is advantageous by the hook member being pivoted by the spring force towards the object and thus being capable of easily engaging its circumferential surface, but nevertheless the hook member can be easily disengaged by moving the lever towards the turning direction, for instance when taking a new engaging position.